Prior art resistance milk flow sensors measure resistance between two electrical conductors separated by an insulator and located in a milk line. Milk flowing across the conductors decreases the resistance between the conductors and a circuit connected to the conductors measures the resistance to determine milk flow.
Prior resistance flow sensors include first and second sections of electrically conductive tubing connected together by a cylindrical insulator such as plastic. First and second leads connect the first and second sections of tubing to a circuit which measures electrical resistance. The first section of tubing, the insulator, and the second section of tubing are connected consecutively in a milking line.
These resistance milk flow sensors have crevices at junctions between the first and second sections of tubing and the insulator. Milk collects in the crevices during use and the crevices are difficult to clean. Some of the prior resistance flow sensors require labor-intensive disassembly for proper cleaning.
Other prior resistance flow sensors include first and second probes which project inside the milk flow lines. The probes are connected to a circuit which measures resistance therebetween.
This type of intrusive milk flow sensor also has the drawback that milk collects around the projecting probes.